Sensitized photographic emulsions



United States, Patent 2,721,79a SENSITIZED PHo'roGRAPHIc EMULSIONS HarryDerek Edwards, Frank Peter Doyle, and Stanley John Palling, Barnet,England, assignors, by mesne assignments, to Eastman Kodak Company,Rochester, N. Y., a corporation of New Jersey No Drawing. ApplicationOctober 18, 1951, Serial No. 252,006

Claims priority, application Great Britain October 19, 1950 8 Claims.cl. 9s 7 This invention relates to photographic emulsions sensitizedwith new dyestuffs of the polymethine type.

An object of the invention is to provide photographic silver halideemulsions of improved sensitivity to light by incorporating therein newpolymethine type dyestuffs as sensitizers.

According to the present invention a photographic emulsion is sensitizedby a polymethine dyestufi having the terminal grouping:

R 451} 1'1 7 I (I) wherein R is either hydrogen or alkyl; R is alkyl;and R is CN, COOH, C0.C6H5 or CO.NH.C6H5.'

Preferably the dyestuif is completed by one of the following groupings:

N/ in 11 R =oH- on=oH-).. N\

n (III) wherein R R and R are alkyl; Z is the residue of a heterocyclicnucleus; and n is either zero or a low integer.

To produce the dyestuiis, an intermediate of the formula:

wherein R R R Z and n are as previously mentioned, X is an anion, and Yis a group reactive with a methylene group, for example, alkylmercapto,acetanilido, or a halogen. v.;..

boiling up to /15 mm.-, and on fractionating'was- 2,721,799 PatentedOct. 25, 1955 The nature of the reaction between the intermediates isexemplified by the following illustrations.

The reaction is preferably carried out in the presence of a basiccondensing agent capable of reacting with the This reaction can proceedat room temperature with good yields, in the absence of a solvent orcondensing agent. (Vila & Ballester; Anales real soc. espan. fis. yquim. (Spain), 4513, 87-8 (1949). Chemical Abstracts 42, 8179 g. AlsoChemical Abstracts 44, 3884 i.)

In other references the presence of a condensing agent such as aceticanhydride is considered desirable, as for instance in the reaction oforthoacetates and orthobenzoates with malononitrile, ethyl cyanoacetate,and dimethyl malonate. (Vila & Jarque, Anales fis. y quim. (Spain), 40,946-50 (1944). Chemical Abstracts 39, 4329 1945.)

Preparations of particular compounds of Formula IV are described in thefollowing Examples 1 to 4. In these and in all subsequent examples,parts given are by weight.

distillation position and the solution was distilled at ordinarypressure.

a dark oil residue which was then distilled under reduced pressure. Theproduct was a dark yellow oil Ethyl alcohol distilled off andleftobtained as a colourless oil boiling at 150-153/ 15 mm. which set toa white crystalline solid.

EXAMPLE 2 2 cyarro-3-ethoxy-2-pr0pen0ic acid C2H5C=C-COOH OCzH: N Cyanoacetic acid (4.25 gms.) and ethyl ortho acetate (10.0 ccs.) were shakenup in a stoppered flask and allowed to stand several days. A solid haddeposited 1;] dicyano-Z-ethoxy-4-p-dimethylamin0 phenyl 1,6 butadiene CNCH3 CN OCzHs CH:

2.70 parts of 1;1 dicyano-2-ethoxy propene, and 3.0 parts ofp:-dimethylamino benzaldehyde were refluxed together in 20 parts ofabsolute ethanol containing 3 parts of piperidine for 1 hour.

The alcohol was removed by distillation under reduced pressure and theresidue cooled. An orange solid was obtained which was filtered off andrecrystallised from dry benzene. M. Pt. 167.

EXAMPLE 6 1;] dicyan-2-eth0xy-3-(3 ethyl-2,2? dihydrobenzthiazolylidene-2 -).-1.-pr0pene 1.94 parts of 2 ethyl mercaptobenzthiazole and 210 parts of ethyl-p-toluene' sulphonate. were fusedtogether.

for 3 hours in an oil bath at 150 C. The meltwas dissolved in-25 partsof ethyl alcohol, 1.36partsof 1;l'- dicyano-2-ethox-y propene, and 3.0parts of triethylamine added, and. the solution: refluxed for 30minutes. On chilling;.the dye.- separated and after filtering anddrying,

was recrystallisedfromidry benzene in the form of bright yellow crystalsmelting at. 190.

4 When incorporating in a silver chloro-bromide photographic emulsionthe sensitivity was extended to 5100 A. EXAMPLE 7 1;]dicyano-2-ethoxy-5-(3 ethyl-2,8 dihydro thiazolinylidene-2-)-1;3pentadiene 1.36 parts of 1;1 dicyano-Z-ethoxy propene and 4.02 parts of2-w-acetanilidovinyl thiazoline ethiodide were refluxed together in 25ccs. of ethyl alcohol containing 3 parts of triethylamine for 30minutes. The solvent was then removed by distillation under reducedpressure leaving an oil which was dissolved in' hot benzene. Thedyestuff was precipitated by petroleum ether and the solid so obtainedrecrystallised from dry benzene in the form of shining blue crystalsmelting. at 138 C.

When the dye was incorporated in a gelatino-silver halide photographicemulsion, the sensitivity was" extended to 5800 A with amaximum at 5250A.

EXAMPLE 8 1;1' dicyano-2-eth0xy-5-(3 ethyl-5-chl0r0-2;3dihydrobenzthiaz0lylidene-2-)-1;3-pentadiene 1.83 parts of 2methyl-S-chloro benzthiazole and 2.0 parts of ethyl-p-toluene sulphonatewere fused together at in an oil bath for 3 hours. The melt was thendissolved in 25 parts of acetic anhydride, 2.1 parts of triethyl trithioortho formate added, and the solution refluxed for 30 minutes, duringwhich time the colour of the solution faded and became dull yellow.

The acetic anhydride was removed by distillation under reduced pressure,leaving a thick oil which was washed several times with ether anddissolved in 25 parts of ethyl alcohol.

1.36 parts of 1;1 dic'yano-Z-ethoxy propene and 3.0 parts oftriethylamine were added to this solution which was refluxed for 1 hour.The alcohol was removed by distillation under reduced pressure and theresidue on cooling deposited a solid dye, which was filtered andrecrystallised from dry benzene. The dye melted at 192 or 210 C. afterrecrystallising several times for analysis.

When incorporated in a silver chloro bromide photographic emulsion. thesensitivity was extended-to 6500 A,

with a maximum of 6200 A.

EXAMPLE 9 1;] dicyano-Z-ethoxy-fi-(1;3;3' trz'methyl 1,-2dihydroindolenylidene-2-)-1;3 pentadiene 2.7 parts of l;ldicyano-Z-ethoxy propene and 9.0 parts of 2-w-acetanilidovinyl 3;3dimethyl indolenine methiodide were refluxed together in 200 cc. ofethanolcontaining 6 parts of triethylamine for 1 hour.

The solution on cooling deposited the dyestufi' which wasfiltered off,dried and recrystallised from dry benzene; in; the. form of. shining:purple crystals melting at 198 C.

When incorporated in a silver bromo iodide photo-- graphic emulsi'onthis dyestutf extended the sensitivity to 5900 A, with a maximum at 5500A.

EXAMPLE l 1;] dicyano 2 ethoxy (3 ethyl-2;3 dihydro 4;5naphthoxazolylidene-2-) 1;3 pentadiene 1.36 parts of 1;1dicyano-Z-ethoxy propene and 5.2 parts of 2-w-acetanilidovinyl 4;5naphthoxazole ethyl-ptoluene sulphonate were suspended in 20 parts ofhot acetic anhydride and 3.0 parts of triethylamine added. A red dyecolour was produced immediately and the suspended solid dissolved.

The solution was refluxed for 15 minutes and then the bulk of thesolvent was removed by distillation. Ethyl alcohol was added to the hotresidue and the resulting solution was then cooled and allowed to standovernight.

The dyestuff which separated was filtered and dried, and recrystallisedfrom dry benzene, having a melting p0int0f2102l1. a .3

When the dye was incorporated in a gelatino silver halide photographicemulsion it extended the sensitivity to 6000 A with a maximum at 5500 A.

EXAMPLE 11 1;] dicyano 2 ethoxy 3 methyl 5 (3 ethyl 2:3dihydrobenzthiaz0lylidene-2-)-1,'3 pentadiene 1.5 parts of 1;1dicyano-Z-ethoxy-l-butene (prepared as in Example 3) 4.5 parts of2-w-acetanilidovinyl benzthiazole ethiodide, 75 parts of pyridine and3.0 parts of triethylamine were refluxed together for 30 minutes.

The dyestuff was deposited on cooling, and after filtering and dryingwas recrystallised several times from dry benzene, having a finalmelting point at 180.

EXAMPLE 12 1;] dicyano 2 ethoxy 3 methyl 5 (1 ethyl 1:2dihydr0quin0lylidene-2-) 1;3 pentadiene 4.4 parts of2-w-acetanilidovinyl quinaldine ethiodide and 1.5 parts of 1;1dicyano-Z-ethoxy-l-butene (prepared as in Example 3) were dissolvedin 50parts of hot ethyl alcohol and 3.0 parts of triethylamine added. f

The solution was refluxed for 20 minutes, and allowed to stand over twodays. p a

A solid product was deposited, which was filtered otf, dried, and thenrecrystallised from dry benzene, to give the dyestuff in the form ofdark green crystals, melting at 166 C.

When the dye was incorporated in a gelatino-silver halide photographicemulsion, the sensitivity was extended to beyond 7000 A, with a maximumat 5200 and 6000 A.

EXAMPLE l3 1.5 parts of 1;1 dicyano-Z-ethoxy-l-butene (prepared as inExample 3) and 5.2 parts of 2-w-acetanilidovinyl-4;5- naphthoxazoleethyl p-toluene sulphonate were suspended in 20 parts hot aceticanhydride and 3 parts of triethylamine added. A red dye colour wasproduced immediately, and the suspended solid dissolved.

The solution was refluxed for 15 minutes and then the bulk of thesolvent was removed by distillation. Ethyl alcohol was added to the hotresidue, to decompose any remaining acetic anhydride and the resultingsolution was then cooled and allowed to stand overnight.

The dyestufl. which crystallised was filtered and dried and thenrecrystallised from dry benzene to give maroon coloured solid melting at226.

When the dye was incorporated in a gelatino-silver halide photographicemulsion, the sensitivity was extended to 6100 A with a maximum at 5400A.

EXAMPLE 14 1;]. dicyan0-2-ethoxy-9-(3 ethyl-2,6 dzfhydrobenzthiaz0lylidene-2-) -1;3;5;7 nona tetraene 5.02 parts of2-w-acetani1ido-1;3;5 hexatrienyl benzthiazole ethiodide and 1.36 partsof 1;l dicyano-Z-ethoxy propene were refluxed together on the water bathin 25 parts of ethyl alcohol containing 3 parts of triethylamine for 10minutes.

A bright blue solution developed, and the alcohol was removed bydistillation under reduced pressure. The residue was cooled, diluted,extracted with benzene and the benzene solution dried with anhydroussodium sulphate. On filtering and distillation of the benzene on thewater bath a solid residue was obtained which was then recrystallisedfrom methanol. The melting point was 168.

When the dye was incorporated in a gelatino silver halide photographicemulsion the sensitivity was extended to the infra-red region of thespectrum.

EXAMPLE 15 2-cyan0-3-eth0xy-6-(3 ethyl-2,6 dihydrobenzthiazolylidene-2-) -2;4 hexadienoic acid 1.3 parts of2-cyano-3-ethoxy-2propenoic acid (prepared as in Example 4) and 4.0parts of 2-w-acetauilidovinyl benzthiazole ethiodide were refluxedtogether in 40 parts of pyridine for 30 minutes. The pyridine was thenremoved by distillation under reduced pressure and the residue cooled,and diluted. The product was filtered, dried, and extracted with drybenzene. On removing the benzene the dye was obtained and purified byrecrystillisation from methanol. The dye melted at 206.

When the dye was incorporated in a gelatino silver halide photographicemulsion the sensitivity was extended to 6000 A with a maximum at 5600A.

EXAMPLE 16 1 benzoyl-l-cyano-2-methoxy-3-(3 ethyl-2;3dihydrobenzthiazolylidene-2-)-1-p'r0pene CCH=C Cells CH3 wherein Rrepresents a member selected from the group consisting of a hydrogenatom and an alkyl group, R R R and R each represents an alkyl group, Rrepresents a radical selected from the group consisting of cyano,carboxyl, benzoyl, and carbanilyl, n represents a whole numeral fromzero to three, and Z represents the non-metallic atoms necessary tocomplete a heterocyclic nucleus containing five atoms in theheterocyclic ring.

2. A photographic silver halide emulsion sensitized with a dyestuffselected from those represented by the following general formula:

wherein R represents a member selected from the group consisting of ahydrogen atom and a methyl group, R and R each represents a memberselected from the group consisting of a methyl group and an ethyl group,R represents a member selected from the group consisting of cyano,carboxyl, benzoyl, and carbanilyl, n represents a whole numeral fromzero to three, and Z represents the non-metallic atoms necessary tocomplete a heterocyclic nucleus selected from the group consising of abenzothiazole nucleus, a thiazoline nucleus, a 3,3-dimethylindoleninenucleus, a 4:5-naphthoxazole nucleus, and a quinoline nucleus.

3. A photographic silver halide emulsion sensitized with a dyestulfselected from those represented by the following general formula:

wherein R represents a member selected from the group consisting of ahydrogen atom and a methyl group, R represents a member selected fromthe group consisting of a methyl group and an ethyl group, and Rrepresents a member selected from the group consisting of cyano,carboxyl', benzo'yl, and carbanilyl.

4. A photographic silver halide emulsion sensitized with a dyestuffhaving the following formula:

c=-o'-orr=c NC CrHs $2115 5. A photographic silver halide emulsionsensitized with a dyestuif having the following formula:

6. A photographic silver halide emulsion sensitized with a dyestuffhaving the following formula:

S NC =0 No from 7. A photographic silver halide emulsion sensitized witha dyestuff having the following formula:

8, A photographic silver halide emulsion sensitized O with a dyestuffhaving the following formula:

NC /CHa O=OCH=CH--N\ NO com, on,

References Cited in the file of this patent UNITED STATES PATENTS2,166,736 White et al. July 18, 1939 2,263,749 White et al'. Nov. 25,1941 2,320,654 Riester June 1, 1943 2,322,015 Hamer et al. June 15, 19432,338,782 Riest'er Jan. 11, 1944 2,340,882 Kendall Feb. 8, 19442,353,164 Kendalliet ala- July 11, 1944 2,511,210 Kendall et al. June13, 1950 2,533,233 Edwards et al. Dec. 12, 1950 2,603,642 Edwards et al.July 15, 1952 2,638,473 Edwards-et-al, May 12, 1953 OTHER REFERENCESChemical Abstract s l6b3l0l (Abstract of Brit. Med. Journal, 1922, I,514-515).

Chemical Abstracts 19:530 (Abstract of Pro'c. Roy. Soc., London, 96 B,317-333, 1924).

1. A PHOTOGRAPHIC SILVER HALIDE EMULSION SENSITIZED WITH A DYESTUFF SELECTED FROM THE GROUP CONSISTING OF THOSE REPRESENTED BY THE FOLLOWING TWO GENERAL FORMULAS: 